1. Field of the Invention
The present invention relates to a photoelectric conversion device and an imaging system.
2. Description of the Related Art
Photoelectric conversion devices, such as charge-coupled devices (CCD) and complementary metal-oxide semiconductor (CMOS) devices are used in many digital still cameras and digital camcorders. Configurations to reduce pixel area are being studied with regard to photoelectric conversion devices.
Japanese Patent Laid-Open No. 2007-243197 discloses sharing pixels to reduce the area of photoelectric conversion elements in accordance with reduction in size. Japanese Patent Laid-Open No. 2007-243197 also discloses differentiating between using insulating isolation regions and junction isolation regions among adjacent photoelectric conversion elements. Specifically, both junction isolation region and insulating isolation region are provided for isolation of photoelectric conversion elements. A transfer gate (gate electrode) is provided by way of an insulating isolation region between photoelectric conversion elements.
While Japanese Patent Laid-Open No. 2007-243197 does discuss differentiating between using insulating isolation regions and junction isolation regions, detailed study is not made regarding the structure and manufacturing method of an isolation region where a transfer gate electrode is provided. Depending on the structure of the isolation region where a transfer gate electrode is provided, deteriorated transfer efficiency, increase leak current, variance in properties of the transfer path, and so forth, may occur.